ATXN7 Repeat Expansion Testing
Description
Pathogenic CAG repeat expansions in the ATXN7 gene have been associated with autosomal dominant spinocerebellar ataxia 7 (SCA7). The pathogenic repeat expansions lead to expanded polyglutamine tracts that form nuclear aggregates and alter the normal function of ataxin-7 protein.
Pathogenicity is dependent upon CAG repeat length according to the following ranges 1-2:
Normal Alleles | Mutable Normal Alleles | Intermediate or Uncertain Alleles | Reduced Penetrance Alleles | Full Penetrance Alleles |
27 or fewer | 28-33* | - | 34-36 | 37 or more** |
*Mutable normal alleles can expand to the pathogenic range in one generation, especially if paternally inherited.
**Repeats longer than 100 are typically associated with childhood onset. Repeats longer than 200 are associated with infantile onset.
Tests That Analyze ATXN7 Repeats
- Genomic Unity® 2.0
- Genomic Unity® Whole Genome Analysis
- Genomic Unity® Lightning Genome Analysis – Neonatal
- Genomic Unity® Lightning Genome Analysis – Pediatric
- Genomic Unity® Lightning Genome Analysis – Standard
- Genomic Unity® Exome Plus Analysis
- Genomic Unity® Exome Analysis
- Genomic Unity® Movement Disorders Analysis
- Genomic Unity® Comprehensive Ataxia Analysis
- Genomic Unity® Ataxia Repeat Expansion Analysis
- Genomic Unity® Retinal Disorders Analysis
- Genomic Inform®